End closure for paperboard containers



March 29, 1949. c. BROOKS END CLOSURE FOR YAPERBOARD CONTAINERS 2SheGts-Sheet 1 Filed Marh 12, 1945 L'wz's U Emzaks March 29, 1949. I..c. BROOKS 5,

END CLOSURE FOR PAPERBOARD CONTAINERS Fil ed March 12, 1945 2Sheets-Sheet 2 QM (VF Mar. 29, 1949 Patented i i I END CLOSURE FORPAPERBOARD CONTAINERS Lewis 0. Brooks, Milwaukee, Wis., assignor ofone-third to Ira Milton Jones, Milwaukee, Wis.

Application March 12, 1945, Serial No. ssasss This inventionrelates toclosures for containers and is a continuation in part or the co-pendingapplication of Lewis 0. Brooks, Serial No. 518,991, filed January 20,1944, now Patent No. 2,398,405, issued April 16, 1946.

In the aforesaid application the container illustrated is made oi paperboard and the shoulder construction at the mouth or the container andwhich supports the closure is produced through a novel manner of foldingthe blank from which the body of the container is made. A flat discsecured on this shoulder and having an aperture larger than the mouth ofthe container at said shoulder so as to leave aledge at the innermarginal portions oi the shoulder cooperates with the ledge to securelyhold the closure in place sealing the open top 01 the container. Theclosure includes a sealing sheet disposed over the disc and wedged intothe aperture of the disc and onto the ledge by a relatively stifl insertbonded to the sealing sheet and ota size to snugly fit the discaperture.

While this construction is admirably suited for containers made 01 paperboard and the like, it is possible to embody the invention in aconstruction wherein the stepped-down inwardly projecting ledge isformed integrally with the body of the container at the mouth-thereof.For

instance, the container body might be molded of glass, pulp, or plastic.and it-is one of the obiects oi. this invention to provide a simple buteillcient and positive unitary sealing closure for such moldedcontainers.

More specifically it is an object of this invention to provide aninexpensive sealing closure for the open tops oi molded or glasscontainers having fiat upright side walls and convenient for packagingmilk, dairy foods, and other 'products, and which in addition to sealingthe mouth oi the container acts to protect the rim of the container atthe mouth against contamination.

with the above and. other objects in view which -willappear as thedescription proceeds, this invention resides. in the novel construction,combination and arrangement of parts substantially as hereinaiterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope oi theclaims.

The accompanying drawings illustrate several complete examples of thephysical embodiment oi the invention constructed according to the bestmodes so far devised for the practical application oi the principlesthereof, and in which:

2 Claims. (01. era-5.5)

. 2 a Figure 1 is a fragmentary perspective-view oi the top portion of amolded container particularly adapted for packaging milk, dairy or otherproducts, and showing the sealing closure 01 this invention appliedthereto;

Figure 2 is a fragmentary cross sectional view through a side wallportion or the container at the mouth thereof;

Figure 3 is a perspective-view oi the sealing closure viewing the samefrom the top side thereof and before its application to the mouth of thecontainer; 7

Figure 4 is a view similar to Figure 1 but illustrating a slightlymodified form of closure tor the container mouth; 1-

Figure 5 is a view similar to Figure 3 illustrating the top side of theclosure shown in Figure 4, before its application to the containermouth;

Figure 6 is a view similar to Figures 3 and 5 illustrating a stillfurther modified type of seal-' ing closure; and

Figure '7 is a fragmentary perspective view of space and permitsconsiderable reduction in the sizes or crates and cartons employed inshipping such containers. However, where square that sided containershave been used the conventional round restricted neck designed to takethe conventional bottle caps andcovers was retained. As a result, thesefiat sided containers were undesirable because of the inconvenience anddimculty attending the removal of semi-solid food products through therestricted necks or such containers. This objection has inthe pastdissuaded the packaging 01 other than liquid food products in the fiatsided containers.

The container of this invention, however, distinguishesirom pastcontainers in that it is provided with flat side walls defining auniformly square or rectangular cross section throughout the entiredepth of thecontainer and terminating in a more or less-fiat rim II atthe upper full open end or mouth of the container.

A stepped-down ledge i2 formed integrally with and projecting inwardlyfrom the side walls of the container around the entire inner periphcryof the mouth thereof adjacent to the rim II provides a supportingsurface I3 spaced a slight distance beneath the top of the rim Ii forthe sealing closure M of this invention.

The sealing closure 14 comprises a relatively thin flexible sealingsheet [5 placed across the open mouth of the container so as to coverthe rim H thereof and wedged into place covering the container mouth bya stifi insert or disc Hi to which it is bonded and of a size and shapeto snugly fit the sides of the rim above the ledge l2 without projectingabove the top of the rim I I. Although the insert ideas not projectabove the top surface of the rim II it nevertheless serves to tightlypress the sealing sheet l5 down onto the supporting surface 13 oftheledge and against the sides of the rim to form a secure Joint at themouth of the container.

As clearly illustrated in Figure 3, it will be seen that the sealingsheet i5 is bonded to the insert l8 prior to application of the closureto the mouth of the container and this is preferably eflected by meansof a permanent adhesive.

The underside of the flexible sealingsheet is adhered to the supportingsurface 13 of the ledge, the top of the rim I I to protect the sameagainst contamination, and the inner sides of the rim adjacent to theledge by means of a repeatedly eflective pressure sensitive adhesive.Such an adhesive enables the marginal portions of the sealing sheet tobe repeatedly lifted to uncover the container mouth and reapplied toseal the container mouth a number of times at will,

The adhesive employed for this purpose may consist in a synthetic waxwith strong adhesive qualities, for example, or may be of the typecommonly used on Scotch tape whose effectiveness for repeated use as asealing medium is well known.

The act of uncovering the container mouth is facilitated by means of anextension of one side edge of the sealing sheet l5 forming a pull tabl'l normally adhered to one of the outer side walls of the container bythe same repeatedly effective pressure sensitive adhesive in the closedposition of the cover. The portion of the strip l5 opposite the pull tabmay, obviously, serve as a hinge by its adhesion to the rim Ii duringuncovering of the-mouth of the container.

If desired, the sealing sheet l5 may be provided with flanges l8integral therewith as shown in Figures 4 and 5 to extend around the topof the rim II and to overlie the sides of the, container to affordbetter protection against contamination of the exterior surfaces of thecontainer over which its contents is likely to be dispensed and toafford better protection against accidental displacement of the closure.These flanges are likewise adhered to the outer side walls of thecontainer by a repeatedly effective pressure sensitive adhesive of thetype previously described, and any one of the flanges may serve as apull tab in opening the container.

In place of the repeatedly eifective adhesive sensitive to pressurealone, it may be advantageous in some instances (depending upon the typeof goods packaged) .to employ a special adhesive sensitive to oractivated by both heat and pressure for attachment of the sealingclosure of this invention to the mouth of the container. Certainsynthetic waxes applied to the closure, one of which is known to thetrade as Flexo C-Light," have such characteristics as to enable theclosure to be sealed in place with a tenacity depending upon the degreeof heat employed, in combination with pressure, during application ofthe closure to the container mouth.

When the proper degree of heat is employed in the initial sealingoperation, such an adhesive acts to securely hermetically seal thecontainer mouth and to afford ample protection against accidentaldisplacement of the closure during handling of the filled container, butpermits the closure to be lifted in the hereinbefore described manner touncover the container mouth for dispensing of the container contents.Also, this particular type of adhesive permits resealing of the closureafter partial dispensing of the container contents merely by theapplication of pressure alone; the adhesive thus becoming repeatedlypressure sensitive after initial opening of the closure to allowrescaling of the container a number of times at will. a

For molded containers of the type shown and which are repeatedlyrefilled by the producer, the degree of heat employed with-pressure ininitially sealing the closure would obviously be less than for paperboard containers or others of the molded type used once and thendiscarded.

Some molded containers, especially those for milk, require thoroughwashing and cleansing and a permanent bond between the sealing closureand container mouth must be avoided. If preferred, however, one marginaledge or flange of the closure which is to act as a hinge may be sealedto the rim or outer side wall of the molded container with a greatertenacity than the remaining portions of the closure by the applicationof slightly more heat to said edge or flange so as to prevent accidentalremoval of the entire closure during opening of the container.

As will be apparent, this same type of adhesive is equally desirable forsealing the end closure of this invention to paper board containershaving similarly designed mouth and of the type shown and described inthe aforementioned copending application of Lewis C. Brooks, Serial No.518,991, flied January 20, 1944. When so employed, it is possible tobond the portion of the sealing sheet which is to act as a hingepermanently to the container by the application of a suitable highdegree of heat (and pressure) thereto during initial sealing. Permanentsealing of the hinged edge is, of course, also possible with such moldedor glass containers as are 'used once and then discarded.

Inasmuch as the sealing sheet is preferably adhered tightly to thecontainer mouth with this synthetic wax adhesive so as to enablehermetic sealing of the container contents, the sealing sheet must inall cases be stronger than the sealed joint to enable the joint to bebroken without improper tearing of the sheet.

When a flanged closure is employed, it may also be desirable to providethe flexible sealing strip IS with perforations I9 along opposite sideedges thereof at the bend line of the flanges as shown in Figures 6 and7 and along which the cover may be conveniently torn open. One side 20of the sealing strip is preferably left imperforate so that it may actas a hinge for the closure disposed either on the top surface of the rimor upon-the outer rear side wall adjacent thereto upon tearing of the.strip along its perforations is to uncover the container mouth asillustrated in Figure 7.

When such perforations are used, the flange opposite the side 20 may beimperforate to act as a pull tab or a special pull tab 2| may beprovided thereon. This tab 2| as shown in Figure '7, is formed by acentral imperforate section of the flange l8 opposite the hinge 20having perforations 22 along its side edges leading from perforations l9similar to the perforations l9 to the free edge of the flange.

The tab 2| facilitates opening of the cover inasmuch as it merelyrequires loosening of a small portion of the flange from the side wallto which it is adhered to enable tearing of the strip along itsperforations in the manner hereinbefore described. Obviously, the outeredge portion of the tab 2! may be left free of the container side wallto facilitate grasping the same.

I the mouth of a multiple sided container having rigid side wallscomprising: a ledge integral with the side walls of the containeran'dspaeddown from the end thereof, said ledge extending entirely aroundthe inner periphery of the mouth of the container; an insert of a sizeto flt snugly into the mouth of the container so as to rest on saidledge; a thin, flexible sealing sheet adhered to the underside of saidinsert and projecting beyond the edges of the insert; a'repeatedlyeffective pressure sensitive adhesive on the underside of said sheet bywhich the marginal portions thereof are removably adhered to the ledgeand the wall surfaces defining and adjacent to the tainer; andrepeatedly effective pressure sensitive adhesive on the undersides ofsaid flanges by which they are adheredto the side walls, said thinsealing sheet being weakened at the junctures of the side flanges to thesheet proper along all but one of the sides, but with its line ofweakness at the juncture of th flange opposite said one side interruptedfor a distance and with the line of weakening turned outwardly to theedge of the flange to define a pull tab so that lifting of said tab andthe application of force thereon tears the sealing sheet along its linesof weakness and leaves the closure hinged to the side of the containeropposite the pull tab.

2. A full opening end closure construction for the mouth of a multiplesided container having rigid side walls comprising: a ledge integralwith the side walls of the container and spaced down from the endthereof, said ledge Extending entirely around the inner periphery of themouth of the container; an insert of a size to fit snugly into the mouthof the container so as to rest on said ledge; a thin, flexible sealingsheet adhered to the underside of said insert and projecting beyond theedges of the insert; a repeatedly effective pressure sensitive adhesiveon the underside of side wall surfaces, and the repeatedly effectivepressure sensitive characteristics of the adhesive on the underside ofthe sealing sheet enabling reclosing of the container mouth afterinitial opening; side flanges on said sealing sheet folded over theadjacent portions of the sides of the container; and repeatedlyeffective pressure sensitive adhesive on the undersides of said flangesby which they are adhered to the side walls, said thin sealing sheetbeing weakened at the junctures of the side flanges to the sheet properalong all but two opposite sides so that one of said unweakened sidesprovides a hinge for the closure while the flange opposite theretoprovides a pull tab so that the application of force thereon tears thesealing sheet along its lines of weaknes and leaves the closure hingedto the sides of th container opposite the pull tab.

LEWIS C. BROOKS.

flle of this patent:

UNITED STATES PATENTS Number Name Date 1,497,159 Porter June 10, 19241,859,523 Neely May 24, 1932' 1,915,503 Schmidt June 27, 1933 1,992,152Yeates Feb. 19, 1935 2,345,486 Leebov Mar. 28, 1944 2,369,975 O'BrienFeb. 20, 1945 2,381,508 Moore Aug. 7, 1945

